a) Field of the Invention
This invention relates to an air-conditioning ventilator usable, for example, in a house, a store or a building other than such a house or store. In particular, the present invention is concerned with an air-conditioning ventilator excellent in heat-exchanging efficiency.
b) Description of the Related Art
In recent years, there is an increasing move toward houses with higher air tightness owing to the installation of window sashes and the like. Due to insufficient natural ventilation, however, air fouled with tobacco smoke and the like tends to stagnate inside rooms or the like. Unless ventilation is sufficient during the rainy season, dew may be formed on walls, thereby inducing growth of mold or the like. Insufficient ventilation is therefore insanitary.
Opening of a window or door of an air-conditioned room for ventilation is however uneconomical, because when the room is air-conditioned for cooling, the temperature of the room becomes higher to reduce the effects of the cooling and when the room is air-conditioned for heating, the temperature of the room conversely becomes lower to reduce the effects of the heating. Further, the opening of the window or door also leads to inconvenience such that noise of cars, an airplane or the like enters the room and that at night, radio or TV sound leaks out and may give an annoyance to the neighbors.
To cope with such problems, ventilating fans provided with a heat-exchanging function have been used conventionally. According to such a conventional ventilating fan, an air outlet passage for exhausting foul indoor air to the outside and an air inlet passage for introducing fresh outdoor air into the room are arranged adjacent to each other, and a thermal conductor made of a metal or the like is disposed between the air outlet passage and the air inlet passage.
When discharging foul indoor air to the outside through the air outlet passage and introducing fresh outdoor air into the room through the air inlet passage at the same time by the ventilating fan, an exchange of heat takes place via the thermal conductor between the air to be discharged to the outside and that to be introducing from the outside, whereby heat is recovered to make smaller a reduction in the effects of cooling or the effects of heating.
Incidentally, the recovery rate of heat via a thermal conductor by a ventilating fan having such a heat-exchanging function is as low as 50 to 70% or so. Upon ventilation, heat is therefore not recovered sufficiently, resulting in a change in room temperature. The air-conditioned pleasant environment cannot be maintained accordingly.
With a view to eliminating the above drawback, an air-conditioning ventilator has been proposed as disclosed in Japanese Patent Application Laid-Open (Kokai) No. HEI 2-219936. This air-conditioning ventilator is constructed to make combined use of an upstream-side heat exchanger with a thermal conductor arranged between an air inlet passage and an air outlet passage and a downstream-side heat exchanger with a thermoelectric module disposed astride the air inlet passage and the air outlet passage.
The combined use of the upstream-side heat exchanger equipped with the thermal conductor and the downstream-side heat exchanger equipped with the thermoelectric module makes it possible to increase the heat recovery rate to some extent. There is however a limitation to such an increase, so that the controllable temperature range is narrow and insufficient.
Further, the upstream-side heat exchanger and the downstream-side heat exchanger are formed in an integral structure, resulting in a large air-conditioning ventilator. Its installation in an upper part of a wall or the like requires a support of a large structure for the air-conditioning ventilator. The air-conditioning ventilator therefore sticks out considerably from a surface of the wall and becomes an eyesore. As another drawback, the air-conditioning ventilator is heavy.